After developing a background of genetic knowledge of Aedes aegypti, future work is to be directed to reproduction, behavior and intraspecific variability in traits of economic importance. Although laboratory-based, these studies complement field research on ecology and genetic control of Aedes aegypti in Kenya, currently supported by AID: A. Research on A. aegypti and related Stegomyia will include: 1. Genetic variability, especially differences between sylvan & urban forms. 2. Vectorial capacity for filariasis and bird malaria. 3. Sexual behavior, emphasizing mating and sex pheromones 4. Genetic control mechanisms, including nutritional, thermal and genetic (hybrid) induction of male sterility, sex ratio distortion, translocations. 5. Improved genetic control methods, including selection & heterosis. B. Research on bionomics of Toxorhynchites brevipalpis, a mosquito larval predator on Aedes aegypti and other container breeders. C. Research on genetic variability in natural populations and on the genetic mechanism controlling photoperiod-induced diapause for Aedes triseriatus (principal vector of California Encephalitis to man) and A. atropalpus. D. Operation of the WHO International Reference Centre for Aedes, where 170 strains and 28 species of mosquitoes are maintained and made available to other research workers.